Yale School of Public Health

On September 20, the United Nations Secretary General convened a Climate Ambition Summit in New York City. A central goal of the summit was for government leaders to commit to no new coal, oil and gas and to submit fossil fuel phase-out plans in conjunction with more ambitious renewable energy targets.

That neither the United States nor any other major country stepped up to make such commitments represented a setback for all of humanity. No amount of wishful thinking will reverse the physical reality that the climate crisis is driven by the burning of fossil fuels. Converting from fossil fuels to carbon-free energy is a climate imperative. But it also is a public health imperative.

Heat-related illness and death are the most direct adverse health effects of climate change. Estimates of annual global heat-related deaths range from 350,000 to 500,000, with 37% of heat-related deaths during 1991-2018 estimated to be due to human-caused climate change. Wildfires kill people directly through burns and asphyxiation, but also account for up to 25% of fine particulate matter air pollution in the U.S. as a whole and up to 50% in some regions of the West.

This summer we in Connecticut experienced first-hand how wildfire smoke travels hundreds to thousands of miles to send people with asthma or other respiratory problems to the emergency room. Floods kill people directly through drowning, but also damage water and sanitation systems, making drinking water unsafe and spreading intestinal pathogens in sewage. Droughts cause water and food insecurity. Heat combined with changing precipitation patterns affect the range and transmission of mosquito- and tick-borne diseases, such as West Nile virus and Lyme disease.    

Climate-related disasters have longer-term health effects that appear to be of substantially greater consequence than acute effects, but have been poorly studied. These indirect effects are caused by disruption of electric power, transportation, communications, water, housing, or medical care infrastructure, as well as by population displacement.

For example, the official death toll from Hurricane Maria in Puerto Rico was 64 deaths, until two epidemiologic studies measured 3,0005,000 excess deaths during the three to six months after hurricane landfall. One of the studies estimated that one-third of the deaths were due to delayed or disrupted access to medical care, such as inability to get medicine, to use electricity-powered home medical equipment, or to travel to a medical facility.

Post-disaster housing or employment instability and residence in crowded shelters are associated with elevated risk of adverse health outcomes, both physical and mental, the latter including post-traumatic stress disorder, anxiety, and depression, which also can be triggered by experiencing the actual disaster itself. Finally, climate change increasingly is a factor contributing to migration, with all of its perils, including drowning in the Mediterranean Sea or sexual violence on the journey through Central America and Mexico to the U.S. border.

Reducing greenhouse gas emissions with all deliberate speed by converting from fossil fuels to carbon-free energy is an absolute necessity to address this burgeoning public health crisis.

But even if the carbon dioxide and methane emissions from human use of fossil fuels did not cause climate change, phasing out fossil fuels still would be a public health triumph due to the reduction in other pollutants emitted when fossil fuels are burned, most notably fine particulate matter. Estimates of the annual number of global deaths from fine particular matter range from five to 10 million, making it one of the leading causes of death in the world. Furthermore, actions to reduce the need for fossil fuels, such as building robust pedestrian and cycling infrastructure to promote walking and cycling as alternatives to cars for short trips, reduce emissions of greenhouse gases, fine particulate matter, and other air pollutants, but also increase physical activity, which boosts physical and mental health.

No new coal, oil, and gas is not a radical proposal. In a major 2021 report, “Net Zero by 2050 – A Roadmap for the Global Energy Sector,” the International Energy Agency (IEA) concluded that beyond projects already committed as of 2021, there is no need for new coal, oil, or gas. The Intergovernmental Panel on Climate Change (IPCC) concluded in its major “Climate Change 2023 Synthesis Report” that emissions of carbon dioxide over the lifetime of existing fossil fuel infrastructure alone will lead to warming of greater than 1.5oC, the aspirational target of the Paris Agreement.

Yet fossil fuel corporations, with massive financial support from the largest U.S. banks, continue to pour tens of billions of dollars into new infrastructure, much of which is designed to last half a century. The IEA and IPCC have made it clear that building such new fossil fuel infrastructure is unnecessary, dangerous, and inconsistent with reaching our climate goals. It also is a disaster for public health and has to stop!

Robert Dubrow is Professor of Epidemiology and Faculty Director, Yale Center on Climate Change and Health at the Yale School of Public Health.